2018 Crop Outlook: May 15, 2018

Spring planting is in full swing and temperatures throughout the Midwest have finally begun to rise to a moderate level. It can never be too early to start thinking about a mycotoxin management plan, and in the mycotoxin industry, spring and summer are key times to monitor temperature and moisture levels to predict what this fall’s harvest might look like for contamination.

Key weather trends to be aware of:

• Aflatoxins are caused by the fungus Aspergillus flavus, which has an optimal growth temperature of 35˚C (95˚F). Warm temperatures combined with little to no rain are ideal for aflatoxins. Aspergillus flavus thrives in drought-like conditions but can also be seen in wet weather at the end of the growth cycle.
• Deoxynivalenol (Vomitoxin) is caused by the fungus Fusarium culmorum or Fusarium graminearum. It is often associated with Fusarium Head Blight (FHB) in wheat commodities and has an optimal growth temperature of 15-25˚C (59-77˚F). Cool nights combined with warm days and high moisture are perfect growing conditions for the fusarium toxins.
• Fumonisins are caused by the fungus Fusarium verticillioides, which has an optimal growth temperature of 30˚C (86˚F). Warm temperatures combined with a rainy germination period are ideal for the growth of fumonisins.

This period of late spring and early summer is when we would expect crops planted in the spring to germinate and thus be most susceptible, directly, to fungal growth and, indirectly, to mycotoxin contamination. Since temperature, moisture, and pest infestation are the causes of fungal growth, another key factor to take into consideration is the planting timeline. According to the American Farm Bureau Federation, the planting pace this year is behind the historical rate. If crops are planted later in the season, then this will push back the germination period, and consequently the crops will be exposed to weather conditions different from the norm. This in itself is not a sure indication of mycotoxin contamination, but it is definitely a factor to keep in mind as weather patterns are monitored this growing season.

Around this time last year, midwestern states such as Missouri were affected by heavy rains and flooding. Extreme weather conditions like those experienced around late April and early May last year (2017) can have a significant impact on mycotoxin contamination. What does flooding mean for mycotoxins? An explanation of how flood conditions can affect mycotoxin contamination and our take on last year’s flooding can be found in our article from last May titled “Mycotoxin Pre-Harvest Outlook for 2017.” Although we haven’t seen the same kind of flooding at this point that we saw last year, it’s important to be aware of how different weather conditions at critical stages of development can affect crop growth.

Stay tuned for more crop updates as we continue to monitor weather patterns and crop development in the coming months.

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